The invention relates to exhaust aftertreatment filters for filtering exhaust from internal combustion engines, including diesel engines, and more particularly to the problem of meltdown during regeneration of such filters.
Exhaust aftertreatment filters for diesel engines are known in the prior art. The filter traps contaminant particulate in the exhaust at closed downstream ends of flow channels. The filter is composed of regenerable material, for example cordierite, regenerated by heat to burn-off the trapped contaminant particulate. Meltdowns have been observed in the center of the downstream outlet side of the filter during regeneration. This is believed due to a large accumulation of soot at the outlet side because of wall-flow characteristics of the flow channels in the filter.
The present invention addresses and solves the noted meltdown problem. The invention improves soot particulate distribution within the filter, to reduce heat concentration and the risk of melting during regeneration, to minimize hot-spot meltdown otherwise caused by high density concentration of particulate during regeneration.